1. Field of the Invention
There are several methods presently used to join structural members, particularly those members that are plates formed of dissimilar metals; for example, plates used in the construction of ships. The use of thin plate and the extensive inclusion of aluminum inserts in steel structure on the new ships being designed today has presented a difficult and labor intensive condition for the Naval architects and the construction trades.
2. Description of the Known Related Art
Current methods to join plates include: to weld causing the material of the plates to fuse together, or to bond using adhesives which attach via properties of the bonding agent(s), or to mechanically fasten by the use of physical force. For example, one current method of welding joins dissimilar metals, such as aluminum structure to steel structure, by an explosion bonded piece of "Deta Couple" which is aluminum on one side and steel on the other. Another mechanical method can be an externally applied deformation or penetration of the plates through the use of bolts, rivets, or clamps. Each of these methods has its limitations and disadvantages:
1. Welding requires that the materials of two or more plates to be joined be compatible metallurgically or molecularly to the fusion process. The heat generated by welding, or by brazing, may result in degradation of some material properties. PA1 2. Adhesive bonding requires that the material of the plate and the bonding agent be chemically compatible and environmentally controlled for proper curing. PA1 3. Mechanical fasteners are both labor and material intensive, and require specialized equipment and training. Mechanical fastening does not produce an optimum structural connection, particularly in the construction of ships.
Further, current methods to join structural members formed of dissimilar metals have the continuing requirement either to inhibit or, preferably, eliminate galvanic action developed by and between the dissimilar metals.